go - Can't create copy of variable of type map[int]Struct in another variable by just assigning one variable to another

Question

I have a Map :

cart := map[10033207:{10033207 3 425 126} 10012761:{10012761 4 40 0}]

I want to create copy of cart in another variable tempCart so that I can modify tempCart for temporary usage in my function. I want that cart value remains the same.

tempCart := cart
//some operation which modifies temp cart and make it
//map[10033207:{10033207 2 425 126} 10012761:{10012761 1 40 0}]

The problem is that when I modify tempCart , somehow cart is also getting modified and becomes equal to tempCart .

Later when I print value of cart I get: map[10033207:{10033207 2 425 126} 10012761:{10012761 1 40 0}] and not the original value that is map[10033207:{10033207 3 425 126} 10012761:{10012761 4 40 0}] .

I can't understand the reason behind it and want to know the solution of how to create a copy of cart .

EDIT: This question has been marked as Duplicate to copy one map to another But I knew how to copy one map to anothor, my prime question was why couldn't I just assign one map to another variable. Why do I have to copy it in a loop.

Answer 1

To Copy a map use

for k,v := range originalMap {
  newMap[k] = v
}